miR‐511 inhibits proliferation and metastasis of breast cancer cells by targeting FGF4

BACKGROUND: In this study, we aimed to explore the functions and molecular mechanisms of miR-511 in breast cancer. METHODS: Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-511 levels in breast cancer tissues; chi-square test was used to analyze the relationship between miR-511 expression level and pathological parameters of breast cancer patients; the proliferation of breast cancer cell lines MDA-MB-231 and MCF-7 were determined by cell counting kit-8 (CCK-8) assay; the migration was determined by scratch wound healing assay and transwell assay; TargetScan was used to predict the binding site between the 3'UTR of fibroblast growth factor 4 (FGF4) and miR-511; and qRT-PCR, western blot and luciferase reporter gene assay were conducted to further validate the targeting relationship between miR-511 and FGF4. RESULTS: The expression level of miR-511 was lower in breast cancer tissues than that in adjacent normal tissues. Lowly expressed miR-511 was associated with larger tumor size, lymph node metastasis and short survival time. In vitro experiments showed that miR-511 modulated proliferation and metastasis of breast cancer cells. It was also confirmed that miR-511 directly targeted 3'-UTR of FGF4 and reduced its expression, and FGF4 overexpression reversed the effects of miR-511 on the malignant phenotypes of breast cancer cells. CONCLUSIONS: Our results demonstrated that miR-511 inhibits breast cancer proliferation and metastasis by down-regulating FGF4 expression, which may be helpful in developing new treatment strategies for breast cancer.